Electrolytic process of making bases of the alkali-earth metals.



UNITED STATES PATENT OFFTGE. 'ANDREIBROGHET AND eEoReEsnANsoN, or PARIS, FRANCE.

' urcmowuc PROCESS OF MAKING BASES OF THE ALKALl-EARTH METAlS.

Specification of Letters Patent.

Patented. Nov. 13, 1906.

Application filed February 14,1901. Serial No. 47.253,

To all whom it may concern:

Be it known that we, ANDRE Bnoonn'r and GEORGES RANSON, citizens of the Re ublie of France, residing at Paris,.F,rance, ave invented hertain new.and useful Improvements in' Electrolytic Processes for Making Bases of the Alkaline Earths; and we do de-.

' clare the following to be a full, clear, and exactdescri tion of the invention, such as will enable ot ers skilled in the art to which it apgertains to make and-use thesame ur process consists, essentially, in electrolyzing a mixture of the sulfids of the alkaline earths with chlorids. .Under these circumstances hydrate of the alkaline earth is formed at the cathode and a deposition of sulfur takes place at the anode without any chlorinv being iven off and without the drawbacks resu ting therefrom. The addition of the chlorid of an alkaline earth to the sulfid has for its object to facilitate the reaction. A small quantity of chlorid serves for an indefinite period, and the final electrolytic reaction may be represented in'the following The whole or a part of the chlorid of the alkaline earth may be replaced by the ohlorid of an alkali; butiif a die hragm be used in such a case, the said chlorid of an alkali passing into the cathode-compartment, it is referable to introdupe it therein directly. ikewise in order to obtain directly the base of the alkaline earth in the pure state the sulfid may be placed in the anode-compartment only and the chlorid of an alkali metal employed in solution in the cathode-compartment. The cathode ma be of any kind.

When an insoluble ano e is employedcarbon, for instancesulfur is deposited more or stance, iron or copper an insoluble sulfid is obtained directly, 'sothat the metallic salt when'precip'itated has no action upon the metallic base, which becomes diffused in the anode-com artment and which can be re covered su sequently, because it is not destroyed in that compartment. Likewise when insoluble anodes are used the dia-' phragms serves no otherpurpose than to enable the bases to be obtained direct y in a pure state. a

ations take p ace in the following manner:

The cathode liquid, which was formed origi-' nally of a solut on of a chlorid of an alkali or of a chloridof an alkaline earth, flows in a continuous manner into the apparatus, becomes charged with the'base of-the alkaline earth, and on passing out is led into crystallizin apparatus in which the base of the alka ine earth becomes deposited by cooling. The latter is separated by centrifugal action in a suitable separator fromthe mother-liquor, which is returned to the apparatus, 850. The anode liquid, consistin of a mixture of the sulfid of an alkaline cart and of a chlorid of an alkali or of an alkaline'earth, may be when needed conducted from the apparatus and filtered, reheated, and subjected to systematic lixiviation in the presence of the sulfid bf an alkaline earth, whereby it-may be kept saturated. This operation may be performed in any preferred way.

In order to prevent the carbonic acid of the atmosphere from having any action upon the other substance, which is not acted upon by alkalies. 4

As above stated, the addition of an alkaline chlorid to the sulfid or as catholyte has for its object to facilitate the reaction. of said substance diminishes the resistance at the beginning of the operation, said resistance beingrelatively high at this moment, owing to the small quantity of the base which is present in the solution. Further, the use of said substance as catholyte enables of obtaining the base of the alkaline earth in apure state: at the cathode, or, in other words, free from sulfid, and the quantity of the base obtained is improved, for the reason that in case there is made use of a die hragm, for, instance, it is the chlorid radical (Cl) which is passing to the anode, thebase being formed at the cathode. The use of the alkaline chlorid has further the purpose, when a soluble anode is made use of, of dissolvin said anode in such a manner as to form a ch lorid of the composes with the sulfite of the alkaline earth The use into sulfid of the metal of the anode and sulfur,- which are separated in the vanode-compartment.

We are aware that sulfide of the alkaline have alreadybeen subjectedito electrolysis,

as' antimony double salt, for recovery of the antimony in metallic form; but in said process it was impossible to obtain the hydrate of the alkaline earth at the cathode, as is clearly shown by the reaction taking place in the baths on the cathode. We therefore do not claim, broadly, the process of electrolyzing the sulfids of the alkaline; but,

Having thus described our invention, what chlorid of the alkaline earth with the base of the alkaline earth, then eiiecting the crystallization of said charged solution and finally causing the base of the alkaline earth to be deposited by cooling substantially as described and for the purpose set forth.

2. The herein-described process for the production of hydrate of the alkaline earths '-which consists in electrolyzing an anode li 'uid, composed of a solution of sulfid of an a kaline earth, and a cathode liquid composed of a solution of chlorid of an alkaline earth, interposing a suitable diaphragm between said solutions causing the so ution of the chlorid of the alkaline earth to circulate in a continuous manner during the electrolysis,

thereby charging the solution of the chlorid of the alkaline earth with the base of the alkaline earth, then eiiecting the crystallization of said charged solution, then causing the base of the alkaline earth to be deposited by cooling substantially as described and f or the purpose set forth.

"3. The herein-described process for the production of hydrate of the alkaline earths which consists in electrolyzing an anode li uid, composed of asolution of sulfid of an 'a kaline earth, and a cathode liquid composed of a solution of chloridof analkaline earth interposing a suitable diaphragm between said solutions causing the solution of the chlorid ofthe alkaline earth tocirculate in a continuous manner during the electrolysis, thereb charging the solution of the chlorid of the a kaline earth with the base of the alkaline earth, then effecting the crystallization of said charged solution, then causing the base of the alkaline earth to be deposited by coolin ,then

separating the base from the mother iquid,

then reexposing the latter to the electrolyzingcurrent, causing simultaneously with these operations the solution of the sulfid of alkaline earth tocirculate in a continuous manner during the electrolysis and finally filtering said solution, reheating and saturating the same with the sulfid oi the alkaline earth before being reexposedto the electric current. i i

In testimony whereof we have hereunto set ANDRE BROCHET. GEORGES RANSON. 

